The present invention relates to an control system which enables a calling party to access through a public telephone circuit a telephone terminal equipment such as a facsimile system to which the control system is added, by the use of various types of telephone set.
Conventionally, control apparatuses for remote control of a telephone terminal equipment such as a facsimile system through the public telephone circuit have been known. For instance, in Japanese Patent Application No. 58-161705 corresponding to Japanese Provisional Patent Publication No. 60-53371 (hereinafter, referred to as the prior art system), there is disclosed an control system, which automatically responds to an incoming call to send an outgoing message, and thereafter, in response to a key signal sent from the calling party, transmits an OK signal representative of permission for information reception (a CNG signal, for instance) to a calling party, and at the same time starts a called party's facsimile system.
FIG. 1 shows the above-mentioned prior art system, in which reference symbols TEL-1 and FAX-1 designate a telephone set of a pushphone type and a fascimile system installed at the side of a calling party, respectively, both of which are connected to one side of a public telephone circuit, i.e., telephone lines L1, L2, the facsimile system (hereinafter referred to as a first facsimile system) FAX-1 serving as a telephone terminal equipment. Connected to another side of the telephone lines L1, L2 through a contact y2-1 of a relay Y-2 are a telephone set TEL-2 and an automatic telephone answering device TAD-1 installed at the side of a called party, respectively. Interposedly disposed between the telephone answering device TAD-1 and the relay contact y2-1 is a photocoupler PC-1 adapted to be turned on by an electric loop current which flows when the telephone answering device TAD-1 responds to an incoming call supplied through the telephone lines L1, L2 and a capacitor (not shown) connected in parallel with the photocoupler PC-1, and then a loop circuit incorporated in the device TAD-1 engages the device with these telephone lines. Further, a relay Y-4 is connected to an output terminal C of the photocoupler PC-1. A multivibrator 3 which is connected to the output side of a remote control circuit 10 mentioned below is followed by a counter 4 which is arranged to generate an output when counting up three pulse outputs supplied from the multivibrator 3, the same multivibrator being arranged to be disabled when supplied at its another input terminal with this output of the counter 4. Further, a relay Y-3 is connected to the multivibrator 3 through an AND gate 5.
Reference numeral 6 denotes a ringing signal generator which cooperates with ON/OFF action of a contact y3-1 of the relay Y-3 effected as mentioned below, to supply a dummy signal to a transfer device ASAP, which signal is the same as or similar to the telephone ringing signal supplied through the telephone lines L1, L2. Since the transfer device ASAP is composed of a known device of the type adapted to call out a preset destination for transfer, a detailed explanation thereof is omitted. This transfer device ASAP is connected, on one hand, to the telephone lines L1, L2 through the relay contact y2-1 and the photocoupler PC-2, and on the other hand, to a facsimile system (hereinafter referred to as a second facsimile system) FAX-2 as a telephone terminal equipment installed at the side of the called party. Further, the output terminal C of the photocoupler PC-2 is connected through an invertor 9 to an input terminal of an OR gate 8, which has another input terminal connected to the ringing signal generator 6 through the photocoupler PC-3 and an output terminal connected to the relay Y-2, the above-mentioned elements PC-2, PC-3, OR gate 8 and invertor 9 forming a relay control means for controlling ON/OFF operation of the relay Y-2, the same relay being connected to an output terminal of a second timer 7 incorporated in the transfer device ASAP.
Reference numeral 10 denotes a remote control circuit having an input side connected to the telephone lines L1, L2 through contacts y4-1, y4-2 of the relay Y-4 and an output side connected to one of input terminals of the said multivibrator 3.
Normally, the transfer device ASAP is omitted in the prior art system, and thus the photocoupler PC-2 is directly connected to the second facsimile system FAX-2.
Next, operation of the prior art system of FIG. 1 will be briefly explained.
When an incoming call from the caller's telephone set or pushphone TEL-1 is received by the called party's telephone set TEL-2, ringing signals are supplied to the telephone answering device TAD-1 through a capacitor, not shown, connected in parallel with the photocoupler PC-1, to make the device TAD-1 start, to thereby turn the photocoupler PC-1 on so as to connect the device TAD-1 to the telephone lines L1, L2 through the photocoupler PC-1. Thereafter, the outgoing message is transmitted from the device TAD-1. If a remote control button of the telephone set TEL-1, the [#] button, for instance, is depressed by the caller during the transmission of outgoing message or after completion of recording an incoming message from the caller, which recording is effected by the telephone answering device TAD-1 operated in its recording mode into which the apparatus is switched subsequent to the outgoing message transmission, a remote control signal corresponding to the depressed button is transmitted to, through the relay contacts y4-1, y4-2, and detected by the remote control circuit 10. At that time, the multivibrator 3 is triggered by an output from the circuit 10 so as to cooperate with the counter 4 to intermittently actuate the relay Y-3 several times through the AND gate 5 which is in an enabled condition. As a result, the contact y3-1 of the relay Y-3 operates to drive the ringing signal generator 6 which applies the dummy signals to the second facsimile system FAX-2 through the transfer device ASAP to start the same system FAX-2. During the time the dummy signals are generated, the relay Y-2 is supplied with an electric current through the photocoupler PC-3 and the OR gate 8, and thus remains energized. Further, the relay Y-2 is maintained in its ON state by an output which is inversion of a L level output from the phontocoupler PC-2 which is rendered ON with start of the second facsimile system, and thus the second facsimile is connected to the telephone lines L1, L2 through the relay contact y2-1, the photocoupler PC-2 and the transfer device ASAP, so that data is transmitted between the first and second facsimile systems, if the caller depresses a communication button or start button (not shown) of the first facsimile.
However, prior art arrangements of this kind are useable for use only with the caller's telephone set of a key telephone or pushphone type which is capable of generating the remote control signal or tone, and thus these apparatuses have been strictly limited in their use. Further, in spite that, in the prior arrangements, when the user effects remote control listening to drive the telephone answering device in its playback mode so as to listen to an incoming message recorded by the device, a remote control signal having been recorded together with the caller's message is reproduced to be supplied to the remote control circuit 10 so that the second facsimile system can erroneously operate, conventional arrangements are provided with no effective countermeasure for prohibiting such malfunction of the second facsimile system. Further, the conventional arrangements have not been so designed as to effect switching between reception/transmission modes of the second facsimile in a simplified manner.